Recently, electric vehicle develops rapidly and the occupancy rate of electric vehicle in the whole vehicle market increases year by year. With the development of passenger electric vehicle, the electric vehicle in long driving mileage with safety and reliability gradually becomes the focus of people's attention. In the technology development of the electric vehicle, each performance of the battery pack of the electric vehicle is the emphasis of technology development.
Battery packs mostly use stamped sheet metal at present, although the stamped sheet metal has some advantages in respects of processing technique, it also has some following disadvantages: firstly, a thickness of the sheet metal used to make the battery pack is thin, which leads the whole battery pack to be not sufficient in modality, rigidity and strength and in turn the whole battery pack cannot meets high requirement on mechanical strength; secondly, the weight of the battery pack which uses the stamped sheet metal is high and the energy density of the battery pack is small; thirdly, the battery packs mostly lacks anti-collision device and anti-crushing device, so when the vehicle collides or is crushed, the batteries inside the battery pack will be crushed easily, thereby resulting in accident such as firing or exploding; fourthly, at present the mounting structure and the protecting structure between the battery pack and the vehicle are independent relative to each other, so the integration of components needs to be improved.